usr/src/lib/libc/gen/popen.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)popen.c	5.5 (Berkeley) %G%";
#endif LIBC_SCCS and not lint

#include <stdio.h>
#include <signal.h>

#define	tst(a,b)	(*mode == 'r'? (b) : (a))
#define	RDR	0
#define	WTR	1

extern	char *malloc();

static	int *popen_pid;
static	int nfiles;

FILE *
popen(cmd,mode)
	char *cmd;
	char *mode;
{
	int p[2];
	int myside, hisside, pid;

	if (nfiles <= 0)
		nfiles = getdtablesize();
	if (popen_pid == NULL) {
		popen_pid = (int *)malloc(nfiles * sizeof *popen_pid);
		if (popen_pid == NULL)
			return (NULL);
		for (pid = 0; pid < nfiles; pid++)
			popen_pid[pid] = -1;
	}
	if (pipe(p) < 0)
		return (NULL);
	myside = tst(p[WTR], p[RDR]);
	hisside = tst(p[RDR], p[WTR]);
	if ((pid = vfork()) == 0) {
		/* myside and hisside reverse roles in child */
		close(myside);
		if (hisside != tst(0, 1)) {
			dup2(hisside, tst(0, 1));
			close(hisside);
		}
		execl("/bin/sh", "sh", "-c", cmd, (char *)NULL);
		_exit(127);
	}
	if (pid == -1) {
		close(myside);
		close(hisside);
		return (NULL);
	}
	popen_pid[myside] = pid;
	close(hisside);
	return (fdopen(myside, mode));
}

pclose(ptr)
	FILE *ptr;
{
	long omask;
	int child, pid, status;

	child = popen_pid[fileno(ptr)];
	popen_pid[fileno(ptr)] = -1;
	fclose(ptr);
	if (child == -1)
		return (-1);
	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
	while ((pid = wait(&status)) != child && pid != -1)
		;
	(void) sigsetmask(omask);
	return (pid == -1 ? -1 : status);
}
Commit	Line	Data
	1	/*
	2	* Copyright (c) 1980 Regents of the University of California.
	3	* All rights reserved. The Berkeley software License Agreement
	4	* specifies the terms and conditions for redistribution.
	5	*/
	6
	7	#if defined(LIBC_SCCS) && !defined(lint)
	8	static char sccsid[] = "@(#)popen.c 5.5 (Berkeley) %G%";
	9	#endif LIBC_SCCS and not lint
	10
	11	#include <stdio.h>
	12	#include <signal.h>
	13
	14	#define tst(a,b) (*mode == 'r'? (b) : (a))
	15	#define RDR 0
	16	#define WTR 1
	17
	18	extern char *malloc();
	19
	20	static int *popen_pid;
	21	static int nfiles;
	22
	23	FILE *
	24	popen(cmd,mode)
	25	char *cmd;
	26	char *mode;
	27	{
	28	int p[2];
	29	int myside, hisside, pid;
	30
	31	if (nfiles <= 0)
	32	nfiles = getdtablesize();
	33	if (popen_pid == NULL) {
	34	popen_pid = (int )malloc(nfiles sizeof *popen_pid);
	35	if (popen_pid == NULL)
	36	return (NULL);
	37	for (pid = 0; pid < nfiles; pid++)
	38	popen_pid[pid] = -1;
	39	}
	40	if (pipe(p) < 0)
	41	return (NULL);
	42	myside = tst(p[WTR], p[RDR]);
	43	hisside = tst(p[RDR], p[WTR]);
	44	if ((pid = vfork()) == 0) {
	45	/* myside and hisside reverse roles in child */
	46	close(myside);
	47	if (hisside != tst(0, 1)) {
	48	dup2(hisside, tst(0, 1));
	49	close(hisside);
	50	}
	51	execl("/bin/sh", "sh", "-c", cmd, (char *)NULL);
	52	_exit(127);
	53	}
	54	if (pid == -1) {
	55	close(myside);
	56	close(hisside);
	57	return (NULL);
	58	}
	59	popen_pid[myside] = pid;
	60	close(hisside);
	61	return (fdopen(myside, mode));
	62	}
	63
	64	pclose(ptr)
	65	FILE *ptr;
	66	{
	67	long omask;
	68	int child, pid, status;
	69
	70	child = popen_pid[fileno(ptr)];
	71	popen_pid[fileno(ptr)] = -1;
	72	fclose(ptr);
	73	if (child == -1)
	74	return (-1);
	75	omask = sigblock(sigmask(SIGINT)\|sigmask(SIGQUIT)\|sigmask(SIGHUP));
	76	while ((pid = wait(&status)) != child && pid != -1)
	77	;
	78	(void) sigsetmask(omask);
	79	return (pid == -1 ? -1 : status);
	80	}